1. Field of the Invention
The present invention relates to a refrigerator, and more particularly, to an evaporator in a refrigerator which has a simple structure and an improved thermal efficiency.
2. Discussion of the Related Art
In general, the refrigerator is used for storing food at cold or freeze. As shown in FIG. 1, the refrigerator is provided with a case 10 having a storage space divided into a freeze room 10aand a cold room 10b, and parts composing a refrigerating cycle such as a compressor 20, a condenser 30, an evaporator 40, a capillary tube (not shown) for cooling down temperatures in the freeze room 10a and the cold room 10b. There is a door 12 fitted at one side of the case 10 for open/close of the freeze room 10a and the cold room 10b.
The operation of the refrigerator is as follows.
The compressor 20 compresses a gaseous refrigerant at a low pressure and a low temperature to a refrigerant at a high pressure and a high temperature. The compressed gaseous refrigerant at a high pressure and a high temperature is cooled down and condensed into high pressure liquid refrigerant as it passes through the condenser 30. The high pressure liquid refrigerant is involved in temperature and pressure drop as it passes through the capillary tube, and in altering into low temperature and low pressure gaseous refrigerant in the evaporator 40 during which the refrigerant absorbs heat from environment cooling down the environmental air. The air circulated by a fan 50 through the evaporator 40 is cooled down and flows into the freeze room 10 and the cold room 10b. That is, the freeze room 10 and the cold room 10b are cooled down by the evaporator 40 in the process of circulating the air through insides and outsides thereof by the fan 50.
Referring to FIG. 2, the evaporator 40 is provided with a refrigerant tube 42 for flow of the refrigerant therethrough, cooling fins 44 attached to the refrigerant tube 42 for obtaining a wider conduction area, and a defrosting tube 46 for removing frost on the refrigerant tube 42 and the cooling fins 44. The refrigerant tube 42 has multiple layers of a continuous `S` bent tubes. The cooling fins 44 of thin panels are arranged across the bent refrigerant tube 42 from external view at fixed intervals parallel to each other and welded thereto. The defrosting tube 46 of bent tube along the refrigerant tube 42 is in contact with the cooling fin 44 and provided with a heater (not shown), such as electric heating coil, therein.
Therefore, according to the background art evaporator in a refrigerator explained above, the environmental temperature is lowered as the liquid refrigerant of a low temperature and a low pressure passed through the capillary tube absorbs heat as the refrigerant evaporates during the refrigerant passes through the refrigerant tube 42. The wider conduction area of the refrigerant tube 42 provided by the cooling fin 44 improves a heat exchange efficiency. Frost on the refrigerant tube 42 and the cooling fin 44 formed by a temperature difference between the refrigerant and the ambient temperature is removed as the refrigerant tube 42 and the cooling fin 44 are heated by the heater provided to the defrosting tube 46.
However, in the background art evaporator in a refrigerator, since the refrigerant tube 42, the cooling fin 44, and the defrosting tube 46 are connected as separate components, a cumbersome process for assembling them is required in fabrication of the evaporator, particularly, in the attachment of the cooling fins 44 to the refrigerant tube 42, the refrigerant tube 42 should be inserted into the cooling fins 44 arranged at fixed intervals and expanded for fixing the cooling fins 44 thereto. And, a contact resistance at welded parts of the refrigerant tube 42 and the cooling fin 44 drops a heat conductivity, with a consequential drop of a heat exchange efficiency. Moreover, in defrosting, minute gaps and contact resistances between the defrosting tube 46 and the cooling fins 44 causes a heat exchange poor, dropping a defrosting efficiency. That is, the background art evaporator has, not only a complicated fabricating process, but also poor heat exchange and defrosting efficiencies, thereby causing to have a low productivity and a low quality as a merchandise.